Fin active regions and source/drain regions that are epitaxially grown are typically formed by recessing and epitaxial growth processes. Accordingly, due to a wet etching process and an anisotropic etching process for forming recess regions, the recess regions may have uneven sidewalls that can be shaped like, for example, spherical balls. Uneven sidewalls are generally not good for the performance of a metal oxide semiconductor (MOS) transistor.